Force characteristics of the flow when it is fed into a radial–slotted gap in the transverse direction

Abstract

The article considers a hypothesis of determining the force and energy characteristics of the flow between the walls at the transverse feed into the gap formed by these walls, with the flow of compressible fluid through the central hole in one of these walls. The force parameters for the continuous flow of the compressible fluid in this gap and the alternating concentric annular zones (caverns) of low (rarefaction) and high (above atmospheric) pressure in them are studied. Despite the fact that the flow in the slot gaps is sufficiently studied, the formation of alternating annular zones of rarefaction and pressure is not applied to an adequate degree. The emergence of annular rarefaction and pressure zones changes the representation about the flow distribution in the radial direction of the gap and requires clarifying the conditions of their emergence and determining the force characteristics. This is especially interesting from the point of view of the energy redistribution of the moving flow in this gap. It was found that the annular zone is formed not only when the flow of compressible fluid turns back into the gap behind the edge of the hole in one of the walls, but also in the gap itself, a regular alternation of subsequent annular zones appears behind the first zone. In this case the first annular rarefaction zone appears on the wall with the hole, and the second - on the opposite wall, and so on. If at least one of the walls is made of an elastic material, then its vibrations are possible under the influence of forces caused by alternating rarefaction with increased pressure. The amplitude of the oscillations depends on the pressure force of the compressible fluid supplied to the gap and on the elasticity of the wall material. The relationship between the flow pressure and its force characteristics during its continuous flow in the gap, causing deflection of the elastic wall and the conditions of its self-oscillations, is shown. The regular annular rarefaction and pressure zones, as they move away from the central hole, are determined using a simplified model of the continuous flow stream in the gap. The model also made it possible to determine the force characteristics of the flow in the gap using receptors containing discrete fluid logic elements, the sensitivity of which is slightly higher than, for example, in manometers and vacuum meters. It is established that the formation of annular zones primarily depends on the pressure and flow rate of the compressible fluid fed through the central hole into the gap, as well as on the velocity of the flow diverging in the gap and the number of regular rarefaction zones and pressure in the gap. Some possibilities of useful application of regular alternation of rarefaction zones with increased pressure between closely spaced walls are shown in various devices and technologies with the formation of self-oscillations, when one of the walls is made elastic in relation to the other (rigid). At this time, devices for testing material samples for the perception of cyclic loads, devices for recognizing the position, orientation and capture of plate parts during automatic assembly have been developed. A device for ejecting and multicomponent mixing of gas, steam and other fluids has been developed. Applications have been found in pulsating devices for the production of gas-liquid mixtures in heat and mass transfer processes, in absorption, rectification, dispersion, emulsification, as well as for vibration cleaning of deposits, for example, cyclone walls, etc.